Pale, soft, exudative (PSE) turkey meat is a growing problem for the industry of further processed poultry meat. The low pH condition due to rapid glycolysis while the body temperature is still high leads to protein denaturation, causing pale color and reduced water-holding capacity. This condition impacts product yield and quality. These studies were designed to estimate the incidence of PSE broiler meat in a commercial plant and to use response surface methodology to characterize the relationship between pH and lightness (at deboning and at 24 h postmortem), expressible moisture, drip loss, and cook loss. Pale fillets had significantly lower pH, greater L* values at 3 and 24 h postmortem, and higher expressible moisture, drip loss, and cook loss. The lower water-holding capacity of the pale fillets was characteristic of PSE meat. Additionally, L* values were measured on 3,554 boneless broiler breast fillets in a commercial processing line. By using the L* value range (>54) from the pale group of fillets as an indication of paleness, approximately 47% of the 3,554 fillets were pale and could potentially exhibit poor water-holding capacity. These results may not represent the entire industry but indicate that PSE chicken can represent a substantial proportion of commercially processed broiler meat.

Beef and pork longissimus dorsi and semimembranosus muscles and chicken breast and thigh muscles were excised 24 hr postmortem from carcasses of marketweight grain-finished feedlot beef cattle, marketweight hogs on a typical finishing diet, and broilers on a commercial grain diet. Muscle samples were immediately ground and formed into patties and stored raw or after cooking, at 4ЊC (cooked) or Ϫ20ЊC (raw and cooked). TBA values (on sample weight basis) of frozen raw samples were higher for beef and pork than for chicken, as was heme iron content. However, TBA values of cooked samples were highest for chicken thigh muscles, which contained the most polyunsaturated fatty acids, at all storage temperatures.

Pale, soft, exudative (PSE) turkey meat is a growing problem for industry and has been associated with rapid postmortem pH decline and loss of protein functionality, similar to PSE pork. This study was designed to estimate the incidence of PSE meat in a commercial plant and use response surface methodology to characterize the relationship between pH, lightness (L* value), and water-holding capacity (WHC). One hundred thirty-four turkey breast fillets were selected from the processing line so that 67 had normal color (lightness), and the other 67 were more pale than normal. Fillets were analyzed at time of deboning (1.5 h postmortem) and at 24 h postmortem for color (L* value), pH, drip loss, expressible moisture, and temperature. Additionally, L* values were measured on 2,995 turkey breasts from the processing line to determine the commercial incidence of PSE meat based on color. The pale fillets had significantly lower pH, greater L* value, and less WHC but equal temperature when compared with the fillets with normal color. The L* value and pH were correlated with WHC as measured by expressible moisture, but L* value seems to have more predictive value. By using the L* value range (>53) from the pale-selected fillets as an indication of paleness, approximately 40% of the 2,995 fillets would exhibit poor WHC. These results suggest that PSE meat can represent a significant portion of commercially processed turkey breast meat and that the L* value measurement could be used to sort turkey meat so that PSE type meat could be used in specialized formulations.

Heat stress is one of the prominent ante-mortem stressors that elicits pale, soft, and exudative meat characteristics in stress-susceptible pigs. Industry reports of exudative turkey meat increase in the early summer with the onset of prolonged high temperatures. To study the effect of seasonal heat exposure on turkeys, 122 17-wk-old Nicholas tom turkeys were subjected in January either to growth temperatures of 16/24 C (night/day) (control) or to elevated temperatures of 32/38 C (night/day) (heat-stressed, HS). Turkeys were processed at 21 wk of age in a manner simulating commercial conditions. Pectoralis muscle samples were taken at 15 min (prechill), 2 h (postchill), and 24 h and analyzed for R-value, pH, and color. At 2 h, the remaining intact Pectoralis muscle was harvested, aged on ice for 23 h, and analyzed for drip loss and cook loss. Percentage mortality and carcass weights were not significantly different between treatments. By 15 min post-mortem, the HS birds exhibited a faster pH decline and had higher R-values that persisted through 24 h. The HS birds were also paler in color and exhibited increased drip loss and cook loss when compared to controls; however, expressible moisture was not different between treatments. In addition, the HS birds had a higher frequency of abnormal birds than controls when birds were grouped as normal (L* < 53) or abnormal (L* > 53).

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